JPH04317936A - Eccentric run correcting device for endless belt - Google Patents

Abstract

PURPOSE:To provide a belt eccentric run correcting device at a low cost, with which eccentric run of a photosensitive belt, etc., can be corrected certainly with a simple mechanism. CONSTITUTION:One of belt guide rollers, 6, shall serve as a belt eccentric run correcting roller, which is to be borne by a non-rotary shaft 18. The two ends of this shaft are pin joined with inclining links 17a, 17b at one-side ends with their other ends pin joined to a blet unit side plate, and these inclinging links are arranged in truncated chevlon. A flange 22 is furnished at the two ends of the roller 6, and a stopper 23 is provided to restrict the angle of links. When the belt runs in dislocation to one side to push the flange 22, the angle of links varies to cause the roller to incline, and the positions where belt points in line in transporting direction contact the roller move toward the center one by one because the belt is free from slippage relative to the peripheral surface to the roller. Thus eccentric run of the belt can be corrected.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt deviation correction device for an endless belt that is stretched around a plurality of rollers that are supported parallel to each other between both side plates of a belt unit.

0002

[Prior Art] Photoconductors in image forming devices such as copying machines, printers, and facsimile machines that use electrophotography are used to facilitate the arrangement of process equipment around the photoconductors and to reduce the height of the device. Belt-shaped photoreceptors are widely used because of their ability to An endless belt is also used as a conveying means for the transfer paper.

[0003] In the endless belt, between both side plates of the belt unit,
It is spanned over a plurality of rollers that are supported in parallel with each other, and is driven in a predetermined direction by one of the rollers.
Due to the slight inclination of the rollers, the slight difference in the diameter of the left and right rollers, the uneven thickness of the belt, etc., the belt meanderes or shifts to one side. When the belt shifts to one side, the end of the belt eventually comes off the end of the roller and cannot be returned to its original position or breaks, making it impossible for the belt to perform its original function.

[0004] Therefore, various devices for correcting belt deviation have been proposed. For example, Tokuho 2-22
As shown in Japanese Patent No. 952, etc., most conventional belt deviation correction devices use a deviation detection sensor and a member that is displaced by a drive source in response to the output thereof, and are mechanically complex. It had the drawbacks of high cost and lack of reliability.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of conventional belt deviation correction devices, the present invention provides a low-cost belt deviation correction device that can reliably correct belt deviation with a simple mechanism. The task is to do so.

[0006]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the belt deviation correction device of the present invention uses one of the plurality of rollers around which the belt is stretched as a belt deviation correction roller, and a belt deviation correction roller that pivotally supports the roller. Both ends of the rotating shaft are connected to belt units at positions symmetrically outwardly shifted from the pins in the axial direction by pins provided at both ends of the non-rotating shaft on a straight line extending parallel to the shaft at a certain distance. A pin is connected to the other end of a pair of links that are pin-joined to a member fixed to both side plates, and between the pair of links, the non-rotating shaft, and the pin on the side provided on the side plate of the link. A trapezoidal link mechanism is formed by the straight line, flanges are provided at both ends of the roller, and the above 1.
It is characterized by being provided with a stopper that stops the rotation of the pair of inclined links at a predetermined angle.

[0007]

[Operation] Since this belt misalignment correction device is constructed as described above, when misalignment occurs in the belt, the belt moves to one side in the axial direction on the misalignment correction roller, and eventually the belt shifts to one side on the misalignment correction roller. If the belt comes into contact with one of the flanges and the belt still approaches, the flange will be pushed together with the roller and shaft by the edge of the belt, the trapezoidal link will be distorted, and the slanted link will tilt, causing the roller to push the edge of the belt toward the flange. The shoulder that touched the will rise and the other shoulder will fall.

As a result, the roller rotates with a slight inclination to the belt conveyance direction, and if the belt and roller do not slip after a point on the belt comes into contact with the circumferential surface of the roller, then the belt conveyance The point at which points on the belt that follow that point in the direction start contacting the roller gradually moves toward the center of the roller, and the belt shifts in the opposite direction. When the belt moves in the opposite direction and comes into contact with the flange on the opposite side of the roller, the roller tilts in the opposite direction, and the belt deviation is corrected in the opposite direction. As a result, the deviation of the belt is automatically corrected, and the belt is always conveyed within a predetermined conveyance width.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing an example of an endless belt-like photoreceptor equipped with a belt deviation correcting device of the present invention and the structure of its vicinity. The photoreceptor belt 1 is stretched around a drive roller 2, a transfer backup roller 3, and an offset correction roller 6 of the present invention, which are pivotally supported on both side plates of a photoreceptor belt unit (not shown). It rotates in the direction shown. The roller 3 is biased by a spring 5 through an arm 4 in a direction to push the belt loop outward, thereby applying tension to the photoreceptor belt 1. A charger 7, an exposure position 10, a developing device 11, a transfer charger 12, a cleaning unit 14, and a static elimination lamp 15 are provided around the photoreceptor belt 1 in the order of its circumferential direction, and the photoreceptor is removed by a known electrophotographic process. A toner image is formed on the belt 1, and transferred to the transfer paper 13 under the action of the transfer charger.
transcribed into. Reference numerals 8 and 9 in the figure represent a backup member that maintains a constant distance between the charger 7 and the exposure device and the photoreceptor belt 1, respectively.

FIG. 2 is a sectional view of the misalignment correction roller 6 in FIG. 1 when viewed in the direction of arrow II--II in FIG. roller 6
is rotatably supported by the non-rotating shaft 18 via bearings 20 provided inside both ends, and is prevented from moving relative to the shaft 18 in the axial direction by a retainer ring 21. Flanges 22 are fixed to both ends of the roller 6. Both ends of the shaft 18 are on a straight line L that extends parallel to this shaft at a certain distance in the standard state, and the bracket 16 fixed to the side plate of the photoreceptor belt unit is connected to the axis of the shaft 18 and the above parallel line. The pins 19a, 1 are rotatable within a plane determined by L.
The other ends of the inclined links 17a and 17b, which are pin-joined at 9b, are pin-joined by pins 19c and 19d. The pins 19a and 19b are axially symmetrical to the pins 19c and 19d, respectively, and are located slightly outwardly. As a result, in the reference state where the axis 18 and the straight line L are parallel, the axis 18 and the inclined link 17
A, 17b, and the portion between the pins at both ends of the straight line L constitute a trapezoidal link mechanism in which the upper base is shorter than the lower base. A stopper 23 is provided at a slight distance inside the inclined links 17a, 17b to limit the rotation angle of the inclined links.

Now, when the photoreceptor belt is driven, the belt 1 shifts to one side in the axial direction of the roller due to the inclination of the roller over which the belt is passed, the unbalance of the diameter, etc. Here, in FIG. 2, it is assumed that the movement is toward the right. As the belt 1 moves to the right side, the right end of the belt 1 finally reaches the flange 2 fixed to the right end of the deviation correction roller 6.
2 and when the belt 1 still moves to the right, the right end of the belt pushes the shaft 18 to the right together with the flange 22, and as a result, the pin joints of the inclined links 17a and 17b with the shaft 18 are separated from each other as shown in the figure. It moves to the right, and as shown in FIG. 3, the inclined link 17a comes into contact with the stopper 23 and stops.

In this embodiment, the inclined links 17a, 17
b is in the shape of a "C", so the inclined link 17a
When the roller 6 is in contact with the stopper 23, the right shoulder of the roller 6 is higher than the left shoulder, and the roller 6 rotates around its own axis. Since the inclination of the roller 6 is set to a slight angle of 1° or less, for example, the tension applying roller 3 shown in FIG. , and is conveyed in close contact with the circumferential surface of the roller 6 without slipping. Therefore, as shown in FIG. 4, if a certain point on the belt 1 conveyed in a predetermined conveyance direction indicated by arrow A starts contacting the roller 6 at a point P in space, this point on the belt P, move in the direction of arrow a on the circumference in a plane perpendicular to the slightly inclined axis of the roller, leave the roller at point P' on the back side of point P, and move in the direction generally opposite to A. get out. Since the roller 6 is slightly inclined, the direction a of the vector of the amount of movement after a point on the belt 1 contacts the roller 6 is slightly inclined with respect to the basic traveling direction A of the belt, so that , the vector itself moves in the axial direction of the roller 6 (in the direction indicated by arrow B). As a result, the starting points of contact with the roller 6 of the points sequentially arranged on the belt 1 in the conveyance direction following the above-mentioned points are P1, P2, P in the figure.
As shown by 3, it sequentially shifts in the direction of arrow B, leaves the roller at points P1', P2', and P3' on the back side and exits in the opposite direction to A. In this way, the belt 1 moves in the direction of arrow B while generally maintaining the conveyance direction A. When the opposite edge of the belt abuts the opposite flange of the roller 6 and pushes it further, the inclination of the roller 6 becomes opposite to that shown in FIG. 4, and the belt moves toward the center according to the above-mentioned theory. As a result, the deviation of the belt is automatically corrected, and the belt 1 is transported within a predetermined allowable transport width.

[0014]

[Effects of the Invention] As described above, according to the present invention, electrical
It is possible to correct belt misalignment with a simple configuration without the need for mechanical detection means or correction members driven by a drive source, which is effective in reducing costs, downsizing the device, and improving reliability. It will be done.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of an endless belt-like photoreceptor equipped with a belt deviation correcting device of the present invention and the structure of its vicinity.

FIG. 2 is a sectional view taken along line II-II.

FIG. 3 is an explanatory diagram illustrating its effect.

FIG. 4 is another explanatory diagram illustrating its effect.

[Explanation of symbols]

1 Endless belt 2 Drive roller 3 Guide roller 6 Misalignment correction roller 16 Bracket 17a, 17b Inclined link 18 Axis of misalignment correction roller 19a, 19b, 19c, 19d Pin 20 Bearing 21 Retainer ring 22 Flange 23 Stopper

Claims (1)

[Claims] 1. A belt deviation correcting device for an endless belt which is stretched around a plurality of rollers that are supported in parallel between both side plates of a belt unit, wherein one of the plurality of rollers is a belt deviation correction roller; Both ends of the non-rotating shaft that pivotally supports the roller are symmetrically shifted outward from the pins in the axial direction by pins provided at both ends of the non-rotating shaft on a straight line extending parallel to the shaft at a certain distance. The other end of a pair of links is pin-jointed to a member fixed to both side plates of the belt unit at a position where the belt unit is fixed to the side plates of the belt unit. A trapezoidal link mechanism is formed by the straight line between the side pins, flanges are provided at both ends of the roller, and a stopper is provided to stop the rotation of the pair of inclined links at a predetermined angle. Belt deviation correction device.